Modelling and control of grid-connected current-source converters for electrolysers

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School of Electrical Engineering | Master's thesis

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Mcode

Language

en

Pages

45

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Abstract

Green hydrogen is a promising solution for decarbonizing sectors that are difficult to electrify. Electrolysers powered by renewable electricity enable its production, making the scaling of these devices and their supporting infrastructure essential to meet growing demand. Power converters are therefore critical for industrial-scale, multi-megawatt electrolysers. Although voltage-source converters are commonly used in grid-connected applications and drives, supplying the low voltage required by electrolysers may need a dual-stage structure, increasing cost and complexity. Current-source converters offer a single-stage alternative for low-voltage, high-current electrolysers, but the technology remains less mature compared to voltage-source converters. This thesis provides an overview of the operating principles of current-source converters, including their ideal-switch equivalent circuit and space-vector model, and draws analogies to voltage-source converters. A carrier-based pulse-width modulation method and a control method based on DC-bus inductor energy regulation are presented. Time-domain simulations are carried out to support the dimensioning of passive components, with a particular focus on the DC-bus inductor and the grid side filter capacitor, as their dimensions have a significant impact on both cost and performance. This work lays the foundation for further research into current-source converter technology as a power supply for electrolysers, including improved modulation methods, analytical methods for component dimensioning, and experimental validation.

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Supervisor

Hinkkanen, Marko

Thesis advisor

Bhakar, Priya
Mourouvin, Rayane

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